Most communications devices have touchscreens. The communications devices generally use a narrow-frame design to improve display effects of the communications devices. FIG. 1 shows a structure of a mobile phone, and FIG. 2 is a sectional view at A-A in FIG. 1. It can be seen from FIG. 1 and FIG. 2 that a housing 1 of a traditional mobile phone needs to be provided with a step structure configured to be adhered to a touchscreen 2. A width of the step structure generally needs to ensure a width of above 0.8 millimeters (mm) for adhesion by a double-sided tape or a width of above 0.3 mm for adhesion by dispensing glue. Requirements for characteristics of the double-sided tape and the glue are may be high to ensure product quality, and when the structure is used, a frame still needs to have a given width to ensure adhesion firmness of the touchscreen. As a result, a frame width cannot be reduced, and narrow-frame development of mobile phones is affected.